Mini monitor on shared peripheral bus

ABSTRACT

A system with a main monitor for a host computer and a second, mini monitor for displaying a portion of the display normally intended for the main monitor. In one embodiment, the mini monitor is connected to the computer over a shared, peripheral bus, such as the universal serial bus (USB). The smaller size of the mini monitor and either compression or slower refresh rates allow it to be connected to the USB just like other peripheral devices.

BACKGROUND OF THE INVENTION

The present invention relates to a second monitor for a computer system,and in particular a miniature monitor for showing a portion of thedisplay of the larger monitor.

There are a number of systems which use multiple monitors. A number ofcompanies produce multiple monitor systems which have a stand with two,three, or four flat panel displays mounted on them. Graphics cards havebeen developed to support multiple monitors. Typically, multipleparallel ports are used to used to connect to each of the monitors fromthe mother board or graphics card.

The Microsoft Windows 98™ software contains a dual monitor mode forallowing the driving of two separate images. For example, a Toshibasatellite XGA notebook can drive an internal and external display at thesame time, one on a notebook's monitor and the other on a separatemonitor, such as the user's desktop monitor. A number of softwareapplications allows splitting of portions of the display between the twomonitors. For example, Powerpoint 2000™ allows a screen show on onemonitor and editing of the same show on another monitor. OutlookExpress™ allows a list of e-mail messages on one monitor, and individualmessages on the other. Other applications allow help screens and errormessages to be displayed on a different monitor. See U.S. Pat. No.6,018,340 for a description of the ‘virtual desktop’ that is implementedin Windows 98, in which the so-called desktop is extended acrossmultiple monitors.

U.S. Pat. No. 5,682,486, issued to IBM, shows a system for the movementof windows, icons, etc. between multiple monitors using a “transport”region into which they are moved on a particular monitor.

U.S. Pat. No. 5,255,361, JP2190926A2, U.S. Pat. No. 5,043,919 et. al.,(IBM), describe the technique of modeling a current-display anddesired-display in computer memory, comparing them to determinedifferences, and sending update commands.

U.S. Pat. No. 4,646,261 describes a means for detecting changes to videomemory and sending only the updated video information to the display.U.S. Pat. No. 5,959,686 describes a system with a primary monitor and aplurality of sub monitors, with a kind of serial daisy-chain forcontrolling the sub-monitors. The sub monitors receive the same videosignal as the main monitor.

SUMMARY OF THE INVENTION

The present invention provides a system with a main monitor for a hostcomputer and a second, mini monitor for displaying a portion of thedisplay normally intended for the main monitor. In one embodiment, themini monitor is connected to the computer over a shared, peripheral bus,such as the universal serial bus (USB). The smaller size of the minimonitor and either compression or slower refresh rates allow it to beconnected to the USB just like other peripheral devices.

By displaying on the second, mini monitor windows which do not updateoften, the amount of bandwidth required is further reduced. For example,the smaller monitor could be used for a stock chart or tickertape,e-mail alert, a calendar, appointment book, alarm clock, etc.

In one embodiment, the existing dual monitor feature of Windows 98 isused. A custom video driver makes the device appear to be an ordinaryvideo card and computer monitor to the Windows operating system and toapplication software. The mini monitor itself will include the USBinterface and a video memory for storing the current screen locally, sothat refreshing need not be done over the USB. A simple displaycontroller for driving the display from the video memory is provided.The more complex video controller operations, such as updating thememory, doing rendering, etc. is done in the host computermicroprocessor or video graphics processor.

The second monitor is powered by said shared peripheral bus.

In another embodiment, the mini-monitor has touch screen capability,allowing it to also function as a control pad where icons from toolbars,etc. are off the main screen. Other interaction buttons, such as“Select”, “Next”, and “Back” are included. These buttons can be used forcontent provided to the mini-monitor over the internet, such as picturesfrom a museum, stock reports, etc.

For a further understanding of the nature and advantages of theinvention, reference should be made to the following description takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a system with a peripheral monitoraccording to the invention.

FIG. 2 is a block diagram illustrating the major elements of thecomputer and peripheral monitor pertinent to an embodiment of theinvention.

FIG. 3 is a diagram of one embodiment of a mini-monitor screenillustrating touch-screen buttons.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

FIG. 1 illustrates a computer 12 having a main monitor 14. A USB 16connects to a number of peripherals, such as a scanner 18. Anotherdevice connected to the USB according to an embodiment of the inventionis a mini monitor 20.

FIG. 2 is a block diagram illustrating the main components of computer12 relevant to controlling the mini monitor, and the mini monitor orperipheral monitor 20. Computer 12 communicates over the USB using a USBinterface 22. The sending of video data can be controlled either by amicroprocessor 24, or a special graphics processor or graphicsaccelerator board 26. The microprocessor or graphics processor operateunder control of the operating system 28 as stored in memory. A customvideo driver 30 modifies the operating system operation as necessary toprovide for the transmission of display data to the peripheral monitor.

A bitmap memory or frame buffer 32 stores the image which is provided tothe peripheral monitor. This can either be a separate area of memory, ora designated portion of the frame buffer for the main display 14. In oneembodiment, an optional transmitted bitmap memory 34 stores the lastvideo data transmitted to the peripheral monitor. Thus, bitmap 32 willbe updated with current desired display information, and could becompared to what has been previously transmitted in bitmap memory 34.This comparison can be used to determine what portions of the displayneed to be transmitted to peripheral monitor 20 for updating.

Peripheral monitor 20 contains its own USB interface 36. The video datareceived is stored in a local video memory 38. A display controller 40refreshes the display with the data in video memory 38. Displaycontroller 40 can be a simple controller that merely reads video memory30 and provides the appropriate pixel information to the display.Optionally, this can be under the control of a software display driverin memory in the peripheral monitor, such as a display driver 42.

In one embodiment, the screen 44 of monitor 20 (see FIG. 1) has adimension of approximately 3″×5″. The actual dimensions can vary, withthe only limitation being the amount of bandwidth on bus 16. Since thereis a tradeoff between the size of the screen and how often the data canbe updated, different size screens can be supported depending upon theapplication.

Video driver 30 will maintain bitmap 32, which contains the desireddisplay image. When graphical commands are issued from the OS or anapplication, these commands are applied to this bitmap, commonly knownas an “off-screen bitmap”. This allows, for example, quick retrieval ofthe value of any pixels without having to retrieve values via USB fromthe external device, which would slow the process and complicate thedevice. The video driver can keep track of which pixels, or which areasor regions of the off-screen bitmap, have been modified by graphicalcommands, and which parts of the off-screen bitmap have already beentransmitted to the external device, and the driver can arrange totransmit just those areas that need to be sent over the USB connectionto the external device. In addition, the driver can attempt to compressthe transmitted data, using any number of well-known bitmap datacompression techniques, such as run-length encoding (RLE). Alternately,a motion compression technique such as MPEG can be used. There is enoughcompute power on the host PC to attempt several different compressiontechniques, choosing the one that gives the best results for a givenblock of pixels. If the video driver maintains a second bitmap thatmodels the current state of the mini monitor (current as opposed todesired), then the driver can examine and compare the two bitmaps tohelp it transmit data efficiently. For example, the processor can detectthat the main change in an area is a color change, which could betransmitted very efficiently as a command of the form: “In rectangle Rchange all pixels having color A to color B”.

There are also many algorithms that could be applied creatively to thisproblem (of rapidly updating the image on the mini monitor). Forexample, if the entire display changes all at once, the system couldtransmit a half resolution image (which takes a quarter of the data),followed by the additional data to bring it up to full resolution. Ifthe mini-monitor is being repeatedly updated, this would have the effectof adaptively dropping the resolution in order to maintain the updaterate. The computer can also identify when the mouse cursor is movingover the mini monitor, and make updating the area under and near thecursor as a first priority.

In one embodiment, the driver doesn't just send every pixel as itchanges. Instead, it constantly collects blocks of data to be sent,placing them in a queue which is emptied by a concurrent process thattakes these queued blocks and sends them over the USB. As anoptimization, if a block is queued that covers rectangle R, it would bereasonable to check that no earlier queued block is covered by R. Inthat case, the older block would be discarded without being sent, as itscontents are obsolete.

Very few applications of this mini monitor require high-speed update ofthe entire display area, so doing compressed updates of only the areasthat change should provide excellent speed-up, on the order of 5× to10×.

The software aspects of this device extend beyond the use of a smartvideo driver. Existing software technology allows tracking whichapplications are running, and detecting when a new application islaunched or shut down. For example, Logitech's Wingman™ products usethis technology to adapt game controllers to whatever game the userruns, without user intervention. This technology can be applied to themini monitor. The user can designate one or more applications whosewindows should always appear on the mini monitor, and the software willdetect when one of these applications is about to display a window,relocating the window instantly to the mini monitor. This technique canbe extended to specific classes of windows, such as “error messagewindows from inside Microsoft Developer Studio”, or “Connecting toInternet” windows, and so on. There are many patterns that can be usedto identify candidate windows to be redirected to the mini monitor,including the name of the parent application, the title of the window,key words in the text of the window, etc. The software can also monitorwhich windows the user drags into (and off) the mini monitor, and“learn” the appropriate set of windows to relocate automatically.

FIG. 3 illustrates one embodiment of a mini-monitor 20 with a touchscreen. Display 44 includes a display area 46. At the top is a tool bar48. In one embodiment, the tool bar containing certain icons from a toolbar on a window displayed on the main monitor. The mini-monitor couldonly have the tool bar, or could have part of the window display aswell. The mini-monitor could function as a control pad for the mainscreen. This frees up main screen space for the primary view of anapplication (such as the contents of a document being edited or the mainview of a game). The mini-monitor can also be used to provide anadditional mode of icon/command selection. The mini-monitor, in responseto touching of the buttons, will send a signal back over the bus to thehost computer which mimics a mouse signal. Alternately, the mouse iconcould be moved over to the mini-monitor for selection.

FIG. 3 also illustrates a “Select” button 50, a “Next” button 52 and a“Back” button 54. One use for these is where a supplier offers asubscription to deliver content through the internet directly to themini-monitor, without having the user consider this as a second monitorfor regular windows. For examples, subscribed pictures from a museumcould be downloaded and displayed, making the mini-monitor a picturefrom. The buttons could be used to go back and forth between pictures.The Select button can cause the computer to open a web site pertainingto that picture (e.g., so the user can buy it). Other services couldinclude announcing an IPO or a drop in stock price of a monitored stock.The user could press Select to open the web site to access more news andoptions. In one embodiment, the delivery of contents to the mini-monitoris wireless, as is the button interaction with the computer. Othercombinations are possible, such as using the bus to deliver the screendisplay to the monitor, but using a wireless connection for the buttoninput to the computer.

As will be understood by those of skill in the art, the presentinvention may be embodied in other specific forms without departing fromthe essential characteristics thereof. Accordingly, the foregoingdescription is intended to be illustrative, but not limiting, of thescope of the invention which is set forth in the following claims.

1. A monitor system comprising: a host computer; a first monitorconnected to said host computer; a second monitor, separate andunattached to said first monitor and smaller than said first monitor andcoupled to said computer via a shared peripheral bus interface; a firstmemory configured to store image information transmitted to said secondmonitor; a second memory configured to store image information to betransmitted to said second monitor; and a video driver in said hostcomputer for providing a portion of a display on said first monitor tosaid second monitor, said video driver being operable to compare saidfirst and second memories to determine whether or not a first portion ofan image displayed on said second monitor is to be modified and a secondportion of said image displayed on said second monitor is to be leftunmodified, wherein image data corresponding to said first portion ofsaid image are transmitted to said second monitor and image datacorresponding to said second portion of said image are not transmittedto said second monitor.
 2. The system of claim 1 wherein said sharedperipheral bus interface is a universal serial bus (USB) interface, andwherein a peripheral device other than said second monitor is coupled tosaid host computer via said shared peripheral bus interface.
 3. Thesystem of claim 2 wherein said second monitor is powered via said sharedperipheral bus.
 4. The system of claim 1 wherein said portion of adisplay comprises a separate window from said first monitor.
 5. Thesystem of claim 1 wherein said portion of a display is provided only tosaid second monitor.
 6. The system of claim 1 further comprising acompression unit for compressing said portion of said display fortransmission to said second monitor.
 7. The system of claim 1 furthercomprising a software operating system controlling said first computer,said operating system controlling the transmission of video data to saidsecond monitor.
 8. The system of claim 1 wherein said second monitorincludes: a display screen; a display controller coupled to said displayscreen; a video memory coupled to said display controller; and a secondshared peripheral bus interface coupled to said video memory.
 9. Thesystem of claim 1 wherein a display screen on said second monitor isless than 8.5 inches diagonally.
 10. The system of claim 1 wherein saidsecond monitor includes a touch screen.
 11. The system of claim 1wherein said second monitor includes icons for control of a display onsaid first monitor.
 12. The system of claim 1 wherein said secondmonitor includes a transmission capability for providing data to saidcomputer on the activation of buttons or icons on said second monitor.13. The system of claim 1 wherein said transmission capability iswireless.
 14. The system of claim 1, wherein the second monitor isconfigured to function as a control pad for the first monitor.